Treatment of textile fiber



Patented Aug. 17, 1943 UNITED :STATES PATEN T OFFICE TREATMENT OF TEXTILE Osborne Coster Bacon, Penns Grove, N. J asslgnor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application May 21, 1940, Serial No. 336,375

4 Claims.

This invention relates to an improvement in the process of'treating textile fiber' with aqueous baths of water-soluble, heteroatomic, longchain-alkyl derivatives .of formaldehyde for the purposeof imparting thereto wash-resistant surface-characteristics such as softness of feel, water-repellency or starch-fixation. More particularly, this invention relates to processes of the aforementioned type wherein textile fiber, such as cotton, wool, silk, rayon or nylon, is impregnated with an aqueous solution of a, compound of the general formula A-CH2-Z, as more fully defined below, followed by a heat-treatment of the fiber, say at a temperature between 90 and 160 0., for the purpose of imparting the quality of wash-resistance, or so-called permanence," to the aforementioned surface characteristics produced by the aqueous treatment.

' It is an object ,of this invention to improve processes of the type aforementioned, in the sense that the desired surface effect, such as softness of feel, starch-fixation or water-repellence, is enhanced or rendered more permanent "or both, or in the sense that a smaller quantity of the aforementioned reagent may sumce to produce the desired effect to any given degree. Other and further important objects of this invention will appear as the description proceeds.

The aqueous treatment processes to which the present invention 'relates are characterized by two principal features. First, the fabric, which may be of animal origin, of vegetable origin, or artificial fiber such as a cellulose ester, acellulose ether, regenerated cellulose or nylon, is

treated at low temperature, say not exceeding 45 0., with an aqueous bath containing dissolved therein a quantity, say up to 8% a compound of the general formula A-CH2Z, as more fully defined below. Secondly, the treatby weight, of

ed fabric, after removal of excess moisture, as

by squeezing or centrifuging, sometimes followed by drying, is subjected to a heat treatment in the absence of moisture, at between 90 and 160 C., for a period of time ranging (inversely with the temperature) from one or two minutes to about half an hour or over. x

The treating agent, for the purpose of accomplishing the results aforementioned, must be characterized by a structure of the general formula A-CHz-Z, wherein A is any organic radical whatsoever provided (a) it is free of water.

solubilizing groups, (b) it contains an alkyl radical, saturated or unsaturated, having a straight chain of at least 7 carbon atoms, (0) it is attached to the CH2 group indirectly, that is through the agency of a non-carbonic atom, such as oxygen, sulfur or nitrogen; while Z is a water-solubilizing radical, that is an organic or inorganic radical containing water-solubilizing groups but attached to the CH2 group through a non-carbonic atom, therebyproviding a theo-- retical point of fission at said OH: group. The nature of this water-solubilizer Z is best understood by reference-to the following typical examples thereof:

(a pyridinium halide), or generally N-(tert)-X i. e. a quaternary-ammonium salt radical);

y ene! -so (an isothiouronium radical);

(phosphonium radical) or a water-soluble salt thereof, such as ammonium, or alkali-metal salt;

- tives of formaldehyde.

Further understanding as to the nature of the reagent of general formula A-CHz-Z may be gathered from the following typical illustrations thereof, which however are not intended to limit the scope of this invention.

Quaternary ammonium derivatives In U. S. Patent No. 2,125,901, permanent starch finishes are produced on cellulosic textile material by the aid of quaternary ammonium com pounds of the general formula.

wherein R is an organic radical free from water-f solubilizing groups, and may be aliphatic or aromatic, straight-chain or branched-chain, saturated or unsaturated, alkyl or acyl; X stands for a non-carbonic link selected from the group consisting of oxygen, ulfur, imino and substituted 'imlno; N(tert) stands for a tertiary basecapable of forming a salt or quaternary compound; and Y stands for the anion of a salt-forming acid. It is stated there, that when R is an aliphatic radical of or more carbon atoms, the fabric becomes particularly smooth and pleasant to handle, and also become water-repellent. As specific illustrations oi?v the agents employable, this patent mentions:

octadecyloxy-methyl-pyridinium chloride:

' C1aHav-O --CH2NCsI-I5-C1 I stearamido-methyl-pyridinium chloride:

CuHss-CONH--CH2NC5HsCl octadecyloxy-methyl-quinolinium chloride; octadecyloxy-methyl triethanol ammonium and various others.

N-carbomethoxy-undecylamino-methyl-pyridinium chloride:

' c1,nn-N-c11,N- ci stearanilido-methyl-pyridinium chloride:

' CnHas-C O-III-OHQ7N CI cetyl-oxymethyl-pyridinium oxalate;

and numerous others.

us. Patent No. 2,146,392 discloses the synthesis, and special utility as water-repellency agents, of compounds of the general formula which is illustrated further by stearamidostearyl-ureido-methyl-pyridinium chloride:

C17H35-CONHCONHCH2NC5H5C1 N-methyl-N-cetylureido methyl pyridinium chloride:

cmnu-N-c oNn-cm-Nmmcn octade'cyl-carbapiido-methylpyridinium (pyridine-sulfate) C1aHuocoNncm'-Nc,n.

Copending application of Fox, Serial No. 815,- 166 describes and claims a series of quaternary ammonium compounds derived from the methylols of higher-alkyland halogen-alkyl sulfonamides which are obtained generally in admixture by amidation of the so-called Reed products. As a typical product of the above type may be mentioned the mixture of cetanc-sulfonamidomethyl-pyridinium chloride,

and related products wherein the cetyl radical is partially halogenated.

Iso-thiouronium' derivatives These are described in British'Patents Nos.

507,207, 507,628 and 511,144 and in copending application of Pikl, Serial No. 320,564, filed February 24, 1940. They are generally prepared by reacting a long-chain acyl amidoor carbamidomethylene halide with thiourea, and may be rep-- resented by the general iormula RYI IICHzQ,

wherein R is a long-chain aliphatic radical free from water-solubilizing groups, Ystands for C0 or O--CO, R is hydrogen or an organic radical, while Q designates an isothiouronium halide radical.

Typical illustrations of this family 01' compounds are:

, stearyl amid0-methy1-is0thiourea-hydrochloride:

NH CnHss-(l ONH-C H,- s *0 NHz.HCl

' and the bis-thiouronium derivative of bis-chloromethylene-distearamido-methane NH.HC1

CnHar-C ONC Hz s c v N H:

N112 CnHzs-C O-N-C Hz- S C NHJIC] Phosphonic-acids and salts thereof These are described in copending application of Engelmann and Pikl, Serial No. 322,766, filed March 7, 1940 (now Patent No. 2,304,156, issued December 8, 1942). They are prepared by reacting with a phosphorus trihalide on the methylol compound of a long-chain acylamide or carbamate, followed by rearrangement and hydrolysis, and may be represented by the general formula wherein R, Y and R have the same significance as above, while M stands for hydrogen or a water-soluble cationic atom or radicaL, As typical illustrations of this g oup of compounds may be mentioned:

stearamido-methyl-phosphonic acid:

C1'lH35CONH-CH2PO (OH) 2 and its ammonium, sodium or pyridinium salts.

Ethers with water-soluble methanol derivatives These may be represented by the general formula wherein R, Y and R have the same significance as above, while B" represents a methylene group carrying further organic or inorganic substituents which are water-soluble. This class of compounds and their synthesis is described in detail in copending application of Engelmann and Pikl, Serial No. 356,356, filed September 11, 1940, (now Patent No. 2,313,741, issued March 16, 1943), and is typified by the following members:

stearamido-methyl-ether of glycollic acid:

CnH35CONH--CH2-OCH2COOH stearamido-methyl-ether of hydroxy-methylstearamido-methyl-ether of diethylene-glycol; stearamido-methyl-ether of sulfo-benzyl alcohol;

hyde or a substance-yieldin formaldehyde, for

instance paraformaldehyde, alpha-trioxymethylene or methylene diacetate.

I am aware that some of the treatments aforementioned with-some of the agents aforementioned have been combined in the art with a formaldehyde treatment for the sake of imparting to the fabric crease-resistance. ment was especially applied to pile fabrics containing a viscose rayon pile for the purpose of rendering the latter crush-proof. However in a l these treatments, a large concentration of formaldehyde was required, say of the order of 15% as referred to the weight of the fabric treated. Also, this treatment had to be applied under strongly acid conditions, say at a pH of 2 to 3. The result, as already mentioned, has been an increase in resiliency of the fiber accompanied by increased brittleness, which was produced by reaction of the formaldehyde or its polymerization products with the fiber. Moreover, it is claimed that the formaldehyde does not react with non-reactive fibers, such as silk, and the process is practically confined to viscose process rayon pile silk back velvets.

My present invention is distinguished from such processes in that the acidity is relatively low; thus, the acidity is not stronger than pH 4.5

This treatand may be as low as pH 5.5 or pH 6.5. The formaldehyde concentration is also-low. In no case does it exceed 8% by weight of the treating bath, and the preferred range is somewhere be tween 0.1% and 3%. As a result of the hydrogen ion concentration employed, no perceptible deposit or reaction of formaldehyde or its polymerization products on or with the fiber takes place, and the resulting textile material is as soft to the feel as, and no more crease-resistant than when no formaldehyde is used, except that the degree of Water repellency acquired by it or the permanence of this water repellency or softness acquired is much greater. It is believed that these improvements are consequent to a stabilizing effect which the formaldehyde exerts upon the water-repellency agent. It will be remembered that most of the water-soluble water-repel lency agents of the type abovedisclosed are decomposed by moisture, especially at warm temperatures. The formaldehyde added according to this invention somehow stabilizes these agents against decomposition by moisture, perhaps through the action, in some manner, of the law of mass-action. That the. addition of formaldehyde to the treatment bath wouldv produce these beneficial results was entirely unforeseen.

Apart from the above two limitations as to acidity and concentration of formaldehyde, the process may follow in all details the processes heretofore employed with the respective reagents of formula ACI-Iz-Z.

Without limiting my invention to any specific details, the following examples are given to illustrate my preferred mode of operation. Parts mentioned are by weight.

Example 1 Baths of the following composition were prepared:

The sodium acetate was added as a buffer to maintain the pH of the solution above 4.5.

Samples of a white, mercerized, cotton poplin fabric were impregnated with the solutions, squeezed to remove excess solution, dried in front of ,a fan, baked for 3 minutes at C., neutralized in a solution of Gardinol (a wetting and cleansing agent) and soda ash, rinsed thoroughly in warm water and dried.

The treated fabric samples were subjected to a spray test in which a continuous, horizontal spray (from a spray nozzle connected to a water line) was allowed to impinge on the fabrics from a distance of 10 inches. The treated fabric samples were held taut in embroidery hoops during the test. The following observations were made on the fabrics at the end of 1, 3 and 4 minute time intervals.

Treating Appearance of fabric surfacev hath for fabric After 1 minute After 3 minutes After 4 minutes Surface Wet Drops on surface.

Surface dry No drops on sur- Surface dry.

face.

Surface very wet.

The purpose of the sodium acetate was to adjust the pH to 4.5 or above.

Samples of a white, mercerized, cotton P plin fabric were treated in the treating baths and subsequently squeezed, dried, baked, neutralized, rinsed and ironed in the same way as described in Example 1. a

The treated fabric samples were subjected to the same continuous spray test as that described in Example 1, except that the spray was allowed to impinge on the fabrics from a distance of 20 inches and the time required to wet the surface was measured. The following observations were made:

Time in minutes required to Treating bath for fabric wet fabric surface Example 3 An unbleached cotton jean cloth was boiled off and dyed a deep navy shade with a vat dye.

A sample of the boiled off and dyed fabric was processed in the known manner with a treating solution containing 3% stearamido methyl pyridinium chloride and 2% sodium acetate crystals. A second sample of the same fabric was processed in the same way, except that the treating bath contained an addition of 4% by weight of the bath of a 37% formaldehyde solution.

The two treated samples were subjected to a standard laboratory spray test in which 250 cc.

of water were sprayed from a nozzle onto a sample of fabric held taut in a frame at an angle of 45 in relation to the spray. The sample treated in the absence of formaldehyde showed some wetting of the upper surface at the points where the water sprays impinged, while the sample treated in the presence of formaldehyde, showed no surface wetting.

Example 4 Samplesof a white, spun viscose process rayon chalis fabric were processed respectively. in the known manner, with a treating solution containing 3% stearamido methyl pyridinium chloride and 2% sodium acetate crystals, and with a treating solution containing in addition 4 parts of formalin per 100 parts of the bath.

The two treated samples were subjected to the standard laboratory spray test described in Example 3, and both completely resisted wetting. On washing these samples together in soap-sodium carbonate solutions, it was found that the sample treated with formaldehyde retained its water repellency much better than the other sample. A similar superiority as to permanence was found also on treating such samples with organic cleaning solutions, such as Stoddard solvent.

- Example 5 A mixed flax and spun-viscose process rayon fabric was treated, in two samples, with a solution containing 3% by weight of stearamidomethyl-pyridinium chloride, and 2% sodium acetate crystals, the solution in one case containing further 3% by weight of formalin. After testing by the standard spray test, the sample treated in presence of formalin proved more highly water-repellent than the other sample.

Example 6 2 parts of stearamido-methyl-thiouronium chloride, 0.4 part of sodium acetate crystal and 2.5 parts of 40% aqueous formaldehyde solution were dissolved in water and made up into a bath of parts total. A sample of bleached, white, cotton jean cloth was impregnated with this bath, squeezed to retain a weight of liquor equal to its own weight, dried in front of a fan, baked for 3 minutes at C., neutralized 'in a solution of Gardinol (see Ex. 1) and soda ash, rinsed thoroughly in warm water and dried. When compared by the spray test to a similar sample treated in a similar bath except that no formaldehyde was added, the first sample was found superior to the second, and showed no sticking, spotting or wetting of the fabric surface.

Example 7 The procedure was as in Ex. 6, except that the bath was made up from 6 parts of the stearamido-methyl ether of glycollic acid, 0.25 pt. of ammonia, 0.5 part of 40% aqueous formaldehyde solution, and water up to a total of 200 parts. The treated sample showed the highest rating of water-repellency under the spray test and was superior to a control sample treated in a similar gatih except for the omission of the formalde- In a similar manner other fabrics may be treated with varying proportions of the aforegoing water-repellent agent or with any other of the agents above discussed. Furthermore, the fabric may be treated with formaldehyde in a separate bath from the .one containing the water-repellency agent. For instance, the fabric may be pretreated with the formaldehyde or the formaldehyde releasing compound and then (with or without drying) treated with the quaternary ammonium or isothiouronium compound etc., in known manner.

In lieu of sodium acetate in the. above examples. any other buffer which is capable of maintaining a pH value between 4.5 and 6.5, may be employed. Borax and sodium-dihydrogen phosphate constitute convenient examples of such alternative buffers.

The advantages of my novel process have already been discussed above. with a given proportion of the water-repellency agent, my novel process gives superior result both as to initial degree of wate'r-repellency and as to the permancncy thereof, that is resistance against washing and dry cleaning. On the other hand, for a given degree of water-repellency less of the water-repellency agent is required. However, an even more important advantage is the fact that the water-repellency agent itself appears to be stabilized throughout the treatment process.

Thus, in the case of the quaternary ammonium compounds, the instability of the agent at higher temperatures in the presence of moisture, makes it necessary in many cases to dry the impregnated fabric carefully at low temperature (say not over 45 C.), before subjecting it to the baking step. This is particularly true of the oxymethylenequaternary compounds, as typified by cetyl-oxymethyl-pyridinium chloride. IBy my improved process, however, the treating agent becomes more stable, and the drying step becomes less critical, and may in some cases be omitted altogether; that is, it may be merged into the baking step.

I claim:

1. In the process of treating textile fibers with an aqueous solution of a compound of the general formula A--CH2Z, wherein A represents an organic radical free from water-solubilizin'g groups, containing an alkyl radical of more than 7 carbon atoms, and being attached to the CH: group through the agency of a non-carbonic atom selected from the group consisting of oxygen,

sulfur and nitrogen, while Z designates a radical containing water-solubilizing groups and adapted thereby to bestow water-solubility on the entire compound, the improvement which comprises than pH 4.5 and not'less than pH 6.5, the concentration of the added formaldehyde being not greater than 8% by weight of the treating bath.

2. In a process of imparting wash-resistant surface characteristics to textile fiber by treating the fiber with an aqueous solution of a watersoluble methylene quaternary ammonium salt having attached to the methylene group an aliphatic radical of at least 7 carbon atoms, followed by a heat treatment at a tempertaure between 90 and 160 C., the improvement which comprises adding to the aqueous bath a formaldehyde yielding agent to form within the bath a and 160 C.

- 4. The process of, treating textile fabric whereby to impart thereto water-repellent characteristics, which comprises impregnating the textile material with an aqueous bath containing from 0.1 to 3% by weight of formaldehyde; then further impregnating the fabric with an aqueous bath containing from 1 to 4% by weight of a stearamido-methyl-pyridinium halide, both aqueous baths having an acidity not greater than pH 4.5 and not less than 5.5; and then heating the fabric in the absence of moisture at a temperature sufficient to decompose said pyridinium compound, splitting ofl' pyridine. i.

bsBoRNE c. BACON. 

